Electroslag guide nozzle

ABSTRACT

The present invention relates to a novel consumable guide nozzle suitable for use in the electroslag welding.

United States Patent 1191 1 1 3,761,674 Bierwith Sept. 25, 1973ELECTROSLAG GUIDE NOZZLE 3,558,845 1/1971 Norcross 219/73 [75 IInventor: Stanton F. Bierwith, San Leandro,

. "31'1"", "nmwumm m4 0 W 7 MW 4 Primary ExaminerE. Goldberg [73Asslgneez Great Canadian Oil Sands, Limited, Attorney-George L Church eta1.

Toronto, Canada [22] Filed: Mar. 29, 1972 [1.8. CI. Th present inventionrelates to a ngvel (:Qnsumable [51 Int. Cl B23k 9/04 id nozzle it bl f si the elecu'gslag welding [58] Field of Search 219/76, 73, 126

[56] References Cited 2 Claims, 3 Drawing Figures UNITED STATES PATENTSHawkins 219/76 PATENTEDSEPZSISFH FIG. III

FIG. 11

FIG. I

ELECTROSLAG GUIDE NOZZLE BACKGROUND OF THE INVENTION Electroslag weldingin general is a process whereby heat is generated by passing an'electriccurrent between an electrode and a ground base to create a weld pool ofthe molten electrode. The passing of the current through the electrodemelts the electrode to provide a weld pool suitable for fusing metalarticles to gether. Recent developments in this area of weldingtechniques include the evolvement of consumable guide nozzles for use inthe electroslag welding technique. A rather detailed description of theelectroslag welding and a particular apparatus suitable therefore can befound in U. S. Pat. No. 3,518,397 issued June 30, 1970.

A consumable guide nozzle generally is a hollow tube through which theconsumable electrode usually in the form of wire passes into the weldpool of the particular welding process being conducted. One purpose ofthe consumable guide nozzle is to direct the electrode wire into thewelding pool of the process being conducted.

The consumable guide nozzle also serves as a'means for 7 adding othermetal components to the weld pool to thereby provide a final weld havinga desired metallic alloy.

Many variations of consumable guide nozzles as well as consumableelectrodes have been disclosed in the prior art. For example, U. S. Pat.No. 3,325,619 issued June 13, 1967 provides a consumable nozzle ofametal alloy having ceramic rings around the surface thereof to inhibitarcing to the metal workpieces which are being welded. U. S. Pat. No.2,137,471 issued Nov. 22, 1938 and U. 5. Pat. No. 3,023,130 issued Feb.27, 1962 each provide procedures wherein the electrode itself is made upof a metal tube containing hard carbide parti cles. U. S. Pat. Nos.2,345,758, 2,510,960, 2,909,778, 3,118,053, 3,215,809, 3,448,241,3,457,388, 3,491,225, 3,531,620 and 3,534,390 each present in variousforms consumable electrodes containing fine metallic particlesencapsulated within a metallic shield or consumable electrodes andconsumable electrode guide nozzles. These compositions generally providean outer tubular body having fine'metallic particles disposed therein.There also is usually designed a means for an electrode guide wire topass through the consum able nozzle.

There are circumstances where it is desired to add to the metal of theconsumable electrode a given quantity of other metals in order toprovide a weld alloy having a given composition and thereby specificphysical properties. Unfortunately, the electrodes and consumablenozzles provided by the hereinabove noted prior art are substantiallymade up of a solid metal tube or shell which encapsulates the metallicparticles desired for the composition of the weld. Thus by following theprocedures of the prior art, the amount of additives as alloys in theweld is substantially restricted to the quantity which can be placedwithin the metal sheaths provided.

DESCRIPTION OF THE INVENTION The present invention is a method forpreparing novel consumable guide nozzles which are comprised of fineparticles of metal bound together around a guide tube. By use of theconsumable guide nozzles of the present invention, a hardfacing alloymetal containing the desired components in the weld composition can beprepared. Specifically, the present invention provides a method forpreparing novel guide nozzles for electroslag welding in a variety ofshapes and forms and containing any metallic composition which isdesired. One embodiment of the novel consumable guide nozzles of thepresent invention can be seen in the illustrations of FIGS. I, II andIII.

Referring to FIG. I, a consumable guide nozzle comprised of guide tube10 which can be any type steel or metal desired is surrounded by amatrix of fine particles of metals which have been compressed, shapedand baked around the surface of the tube to provide a consumable guidenozzle which when added to the melt of the consumable electrode providesa final metal alloy hardfacing composition of the desired physicalcharacteristics.

FIG. II illustrates a consumable guide nozzle comprising metallic guidetube 12 similar to that of guide tube 10 in FIG. I wherein thecomposition of the metal-' lic particles which have been fused aroundthe guide tube can comprise particulate metallic carbides blended withother metal components to provide the surface often desired when hardsurfacing by electroslag technique.

FIG. III illustrates a consumable guide nozzle having guide tube 14similar to that of FIGS. I and II surrounded a matrix of metallicparticles which can be similar to those disclosed in FIGS. I and II withthe variation that the design of the guide nozzle provides that as theweld pool rises, increasing quantities of the alloy of the guide nozzleare added to the slag pool thereby providing a variation of metallurgyacross the surface of the weld. This is particularly useful in hardsurfacing wherein different parts of the wear surface of the workpiecerequire varying physical properties.

in order to more specifically define methods and compositions of thepresent invention, the following examples are herein presented.

Small metal particles passing through a screen mesh were blendedtogether as follows. grams of ferrochorme, 8 grams of ferromanganese, 4grams each of ferromybdenum, zirconium and titanium were blendedtogether and added to a container of 20 milileters of 60 percent ofsodium silicate in water. The metal particles were agitated in thesodium silicate until all were surface wetted. Thereafter the excesssodium silicate was drained and the etallic particles were placed in amold having a 195 millimeter long hollow center tube having. a 3%millimeter internal diameter and a 7 millimeter outside diameter in amanner that the metal particles surrounded the outside of the tube. Thecomposition was thereafter placed in a mold and placed in a press. Themold was subject to a pressure of 2,000 psi and was thereafter baked inan oven at 200 F. for 2 hours. At the end of the time a formed, driedconsumable nozzle of the components disclosed was provided. The totalweight of the consumable nozzle including the center steel guide tubewas 200 grams. By way of comparison, a metal sheath was provided of thesame dimensions as the previously disclosed consumable nozzle and thesheath was filled with the me- .tallic particles of the identicalcompositions of that shown in the example above. The tube held a totalof 75 grams of the particles whereas grams of the particles werecompacted in the compressed baked nozzle.

One of the specific advantages of the method of the present inventionfor preparing the novel consumable nozzles herein disclosed is the factthat the nozzles may be formed to any configuration which is required inorder to provide the necessary hardfacing to a specific area. Forexample, the consumable nozzle having a 90 angle can be formed so as toprovide for the surfacing of a corner of a metal object.

Thus the present invention provides a novel consumable guide nozzlesuitable for use in electroslag welding comprising a central guide tubehaving a coating of fine metallic particles on the outer surface thereofcomprsing at least 50 weight percent of the nozzle. The presentinvention also provides a method for preparing consumable guide nozzlessuitable for use in electroslag welding comprising blending finemetallic particles with a sufficient quantity of a liquid wear hardeningadhesive to wet a substantial amount of the particles, coating the outersurface of a metal guide tube having openings at both ends with themetallic particleadhesive blend and thereafter heating the coated tubeuntil the coating has substantially hardened.

I claim:

1. A consumable guide nozzle suitable for use in electroslag weldingcomprising a central hollow metallic guide tube open at both ends havinga coating of fine metallic particles combined with a heat hardeningadhesive and adhered to the outer surface thereof, said fine metallicparticles comprising at least 50 weight percent of the whole noule.

2. A composition according to claim 1 wherein the heat hardeningadhesive is sodium silicate.

1. A consumable guide nozzle suitable for use in electroslag weldingcomprising a central hollow metallic guide tube open at both ends havinga coating of fine metallic particles combined with a heat hardeningadhesive and adhered to the outer surface thereof, said fine metallicparticles comprising at least 50 weight percent of the whole nozzle. 2.A composition according to claim 1 wherein the heat hardening adhesiveis sodium silicate.